Dipping form for making dipped rubber articles



Oct. 27, 1936. H, BECHER ET AL 2,058,552

DIPPING FORM FOR MAKING DIP PED RUBBER ARTICLES Filed Jan. 25, 1936 INVENTORS 3(arold fiether BY Jacob -$l'ein WW5 4, ATTORNEY5 Patented Oct. 27, 1936 PATENTQQFIFICE v 2,058,552 v V j DIBPING FORM FORMAKIN'G harsh f RUBBER ARTICLEfi uh-oh Becker and Jacob stein; network, N.-Y. l

- 3 said Becher assignor to said Stein "Applicants January 23, 1936, s'e'r iar 91 some Ourinvention relates to a new and improved dipping form for making dipped rubber articles. One of the objects of our invention is to provide an improved form for making rubber articles from latex and otherdisp'ersions or solutions of rubber, by meansof the dipping process.

Another object of, our invention is to provide an improved form for making adipped article made of rubber, soas to produce a rubber article whose wall er varying thickness,

Anotherbbje ctiof our invention is to provide a form 'for saidp'urposewvhereby the article will be provided with a heavy and reinforcing edge, which-willbe thicker thanthewall 0f the body of t e article.

rhe invention applies to 'the mtmacture of rubber gloves, rubber'flnger cots,f'and to nuc'an'be made by the dipping process.

Other objectsbf 'our invention willjbe set forth in the following,description andfdrawing which illustrates-a preferred 1 embodiment thereof, it

,being understood that they above statement of the'objects of our invention is intended generally'to explain the same without limiting it in any manner. s

" Fig.1 is a perspective view partially in section,

which; diagrammatically shows oneembodiment of the "improved form. mo g. 2'isa view sinrilarto Fig. 1', showing a "Fig? 3 isa perspective view of a third embodiseconjd mbodiment.

- It has heretofore been well known to make rubber articles by the dipping process, with the use of forms made of porcelain, wood or other materials. Said forms had smooth outer surfaces, which were substantially non-porous.

It has also been proposed to use plaster of Paris for making an entire form. Such forms are dipped into latex or other dispersions or solutions of rubber until a filnr of the rubber is deposited upon the form. This film may be allowed to dry and the thickness of the wall of the rubber object can be built up, if desired, by means of successive dippings.

We have found that it is possible to produce a rubber object having a rubber wall of varying thickness, by using an insert which is made of plaster of Paris, in a form which is made of wood or porcelain or like material.

As shown in the annexed drawing, the body I of the form is made of wood or porcelain or any other suitable material. Said form has a top surface la.

2 is located within insert, 5.

5Claims. (ems-41) v In the'embodiment shown in Fig. 1, the wall of theform [is provided with a helical groove, in which theplaster of Pafls member 2 is located. The wall of the form" Ican'be provided with a groove, and the plaster of Paris in the wet and plastic form, canbe placed within said groove, andthe plasterof'Paris rnaterial can-then be allowed'to'set .or harden; Said helical groove canbe'ofany desired height, andit'may have any number of turns. In this particular embodiment, theouter surface of the'plaster of Paris member the surface of the main body ofsaidmould. =1 1 a When a mould of this type is used for dipping, this resultsin the'formationqof a rubber object having a relatively thin wall, .6, and having a.

thickened edge-portion 1, which is shown" diagrammatically in Fig. 1.

. i In the embodiment shown in Fig. 1, a single and annular plastenof Paris member 3 is formed in a suitable annular recess or groove of the mould I.

In the embodiment shown Fig. 3, two plaster of Paris inserts 4 and 5 are provided, and the heightof the insert 4 exceeds theheight of the Theuse'fof the fmo'uld, shown in Fig. 1 produces ,two thickenedwall-portions 1 and 8.

,The wall-portionlb of the mould can be of any desired height.

When this form is utilized for dipping, ex-

' peri ence has shown that "a thicker deposit of the porosity than said plaster of Paris. The plaster of Paris exercises a differential surface effect, which may be either a surface-tension effect or an adhesion effect, or a capillary effect.

It is thus possible to use the composite form by means of a single dipping or by means of repeated dippings, thus forming a rubber object whose Wall is thicker adjacent the plaster of Paris material, than at the wood, porcelain or corresponding and relatively non-porous material.

The latex may be permitted to dry between successive dippings, although the best eifect is secured by means of a single dipping.

In order to allow the plaster of Paris insert to exert this differential effect, it is desirable that pounding ingredients of any suitable type may be added. Said ingredients may include vulcanization accelerators and the like. 1

These thin rubber objects are ordinarily vulcanized by means of the cold cure with-sulphur chloride or the like, so that it is not necessary to add any sulphur or anyother vulcanization ingredient to the dispersion and we prefer to use this type of dispersion. However, it would not be departing from our invention it sulphur or other vulcanizing material was a part of the solution or dispersion into which the form is dipped, and-we can use heat curing.

We do not wish to be limited to the use of a member'or insert which is made of plaster of Paris. We can use other materials which become plastic when mixed with water, and which set or harden. For example, the insert can be made from a mortar which can be made by mixing slaked lime and water and filling material such as sand.

Likewise, we can use the so-called' hydraulic cements. I

For example, said insert or inserts can be made of Portland cement.

Likewise, we can use the magnesium oxy-chloride cement, which can be made by mixing 25 grams of calcined powdered magnesite with 10 cc.

of magnesium chloride solution (24 B.).

Likewise, the desired capillary action can be secured by making the mould of wood or porcelain or metal or other relatively non-porous ma- .son skilled in the art, and. we do'not wish to be limited to the examples or to the details heretofore specified.

Theform shown in Fig. 1,. or in. any other figfor the removal of the trimming edge. The parts 10 ofthe form may be made in any desired number of pieces, whichrcan be fastened to each other.

plaster of Paris member or members may project beyond the remaining surface of the mold, said member or members may be arranged in any pattern or have any desired design or designs impressed or otherwise formed therein.

We have shown a preferred embodiment of our invention, but,,it, is. clear that numerous changes and omissions can be made without departing from its spirit.

We claim:'-

1. A dipping form for usev in making dipped rubber articles, saidform having a. composite wall the rubber dispersion having greater adhesion to one portion of said wall than to another por-- tion thereof, whereby a rubber article can be formed whose wall is of difierent thickness.

2. A dipping form for making. a. dipped rubber article having a lip portion which is thicker than the body portion of said rubber article, said form having a compositewall, the rubber dispersion having greater adhesion to that portion: of the wall of said. form. at which the lip of the rubber Q5 article is to. be formed, than at the adjacent .portion of said form.

3. A di'pping'form'formakin'g dippedrubber articles, said form having acomposite wall,a portionof said wall being made of plasterof Paris. &0

4. A dipping form for making dipped rubber articles, said form having a composite wall, a portion of said wall being made of plaster. of Paris, the. remainder of said wall beingv less porous h than the plaster of Paris. I

5. An improvedv dipping form tor-making dipped rubber articles, said form havinga composite wall, only a portion ofh sald. wall being composed of a set-hydraulic. cement, the remainder of said wall being made.- of --material to W which the rubber dispersion has. lower adhesive I properties than to said hydraulic cement.

I-IAROLD BECHER. JACOB STEIN. 

